Monday, May 5, 2008
7-17

Nisin biosynthesis by Lactococcus lactis in bioreactor using diluted skimmed milk as culture media

Luciana J. Arauz, Angela F. Jozala, Gabriel S. Pinheiro, Priscila G. Mazzola, Adalberto Pessoa Jr., and Thereza C. V. Penna. Department of Biochemical and Pharmaceutical Technology, School of Pharmaceutics Sciences, Avda. Professor Lineu Prestes, 580, Bloco 16, São Paulo, 05508-900, Brazil

Nisin, a bacteriocin composed by 34 amino acids with a molecular mass of 3.3KDa, is produced by L.lactis, this biomolecule is active against Gram-positive organisms including bacterial spores, but it is not generally active against Gram-negative, yeasts or fungi. Nisin is widely used as a natural preservative in the food industry and is being considered for use in health care products. for human and veterinary uses. This study has been developed to optimized large-scale nisin production in skimmed milk aiming low-costs process and stimulating its utilization. L. lactis ATCC11454 was assayed in a fermentor with 1.5L of diluted skimmed milk at 25% of standard concentration (2.27gtotal solids) at: (i)airflow 0.5 L.min-1 (30ºC/200rpm/36h) and (ii)airflow of 1L.min-1 (30ºC/100 rpm/36h), both without pH control. The titers of nisin expressed and released in culture media were quantified and expressed in arbitrary units (AU.mL-1 of medium) by the agar diffusion assay utilizing L.sakei ATCC15521 as sensitive indicator microorganism. The highest nisin activity was detected after 12h (7298.61AU.mL-1) and 4h (4049.39 AU.mL-1) of fermentation process, respectively. The results show that the dilution of skimmed milk supplied the nisin expression from cells into media and it was strongly affected by fermentation process conditions. The utilization of diluted skimmed milk as cultivation substrate is an important factor to reduce the production costs of this biomolecule high value-added and increase the commercial application of nisin. Furthermore, the utilization of milk subproducts as milk whey (industrial dispose) can be exploited to reduce the environment pollution.

See more of Poster Session Two
See more of General Submissions

See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)